1. Field of the Invention
This invention is related to a window regulator which drives a door glass of a vehicle upward and downward.
2. Related Art
In a window regulator which drives a door glass of a vehicle, the door glass is fixed to an endless belt in a ring shape which is wound around a pulley rotated by a motor so that the door glass is moved up and down along a guide rail.
The window regulator of this movable belt type is adopted in many kinds of window regulators, since it has higher durability and generates less noise than a movable wire type.
However, when the belt is loosened by a creep phenomenon during long use, transmission of movement force of the pulley cannot be attained well. Therefore, the belt has to be installed with tension thereon to prevent it from loosening.
The inventors have proposed a regulator as shown in FIG. 23 (Japanese Laid-Open Patent Publication No. 4-321853).
In this regulator 94, fixed slider 100 is fixed to carrier plate 98 which is fixed to door glass 96. The fixed slider 100 moves with carrier plate 98 along guide pole 102 which is installed on a door panel of a vehicle. Movable slider 104 is guided along guide pole 102.
A tension application member which is formed by spring 106 is installed on movable slider 104 and biases movable slider 104 away from fixed slider 100. The ends of belt 108 are connected respectively to movable slider 104 and fixed slider 100 to form a ring so that belt 108 is applied with tension and is prevented from loosening.
Thus, a tension application member is installed at a place which is offset from the movement path of belt 108 so that no friction force is caused at the connection portions of the ends of belt 108 and the durability is high.
In belt 108, engagement holes 112 which engage pulley 110 need to be made. Further, belt 108 needs to have a minimum width, since it needs sufficient pulling strength. Thus, pulley 110 which is installed at the upper portion of regulator 94 also needs to be of a minimum thickness. Since a space in the width or transverse direction of a vehicle door on the upper portion of the door is small, pulley 110 is likely to interfere with the door panel.
From the relation to the height of the door, a sprocket (not shown in the figure) which is driven by motor 113 needs to be offset from the motor. The conventional regulator 94 cannot be installed as desired, because installation freedom at the lower portion of the door is limited. Moreover, movable slider 104 which moves along through shaft 114 and fixed slider 100 must be assembled together so that a tension application member which applies tension to belt 108 is formed. Therefore, the window regulator assembly operation is complicated.